1. Field of the Invention
The present invention relates to an apparatus for scanning an original. More specifically, the present invention relates to an apparatus for scanning an original which is employed for the electrophotographic copying machine, facsimile, document file or the like and scans an original while exposing the same.
2. Description of the Prior Art
One example of the conventional apparatuses for scanning an original is disclosed, for example, in the Japanese Patent Publication No. 20428/1983 published on Apr. 22, 1983, the Japanese Utility Model Publication No. 3297/1983 published on Jan. 26, 1974 and so forth. Since these conventional techniques employ a lens whose conjugate length varies with copying magnification, the position of the reflecting mirror is required to be moved in parallel with the optical axis of the lens every time a magnification changing operation is performed. Accordingly, it is complicated to set a wire for driving a reflecting mirror and therefore the overall mechanism is also complicated. With such a complicated mechanism, improvement in reliability and reduction in cost are impossible.
In addition, one example of the apparatuses for scanning an original capable of adjusting a length of a chain or wire for driving the reflecting mirror is disclosed, for example, in the Japanese Utility Model Publication No. 35717/1979 published on Oct. 30, 1979. However, this scanning apparatus has also a complicated mechanism, having the same problem as that of the prior art.